diff --git a/php/src/A.php b/php/src/A.php
index a3973ca..75f0284 100644
--- a/php/src/A.php
+++ b/php/src/A.php
@@ -177,11 +177,12 @@ class A {
     return $pvalue;
   }
 
-  static final function shift(?array &$dest, int $count=1) {
+  static final function shift(?array &$dest, int $count=1, $default=null) {
     if ($dest === null) return null;
     $values = array_slice($dest, 0, $count);
     $dest = array_slice($dest, $count);
-    return $count == 1? $values[0]: $values;
+    if ($values === []) return $default;
+    else return $count == 1? $values[0]: $values;
   }
 
   static final function pop(&$dest, $key, $default=null) {
diff --git a/php/src/db/Capacitor.php b/php/src/db/Capacitor.php
index 0fee8b5..5551f1b 100644
--- a/php/src/db/Capacitor.php
+++ b/php/src/db/Capacitor.php
@@ -1,6 +1,7 @@
 <?php
 namespace nulib\db;
 
+use nulib\cl;
 use nulib\php\func;
 use nulib\ValueException;
 use Traversable;
@@ -168,6 +169,13 @@ class Capacitor implements ITransactor {
     return $this->storage->_delete($this->channel, $filter, $func, $args);
   }
 
+  function dbUpdate(array $update) {
+    return $this->storage->db()->exec(cl::merge([
+      "update",
+      "table" => $this->getTableName(),
+    ], $update));
+  }
+
   function close(): void {
     $this->storage->close();
   }
diff --git a/php/src/db/CapacitorChannel.php b/php/src/db/CapacitorChannel.php
index c7265bb..df96e2a 100644
--- a/php/src/db/CapacitorChannel.php
+++ b/php/src/db/CapacitorChannel.php
@@ -482,6 +482,10 @@ class CapacitorChannel implements ITransactor {
     return $this->capacitor->delete($filter, $func, $args);
   }
 
+  function dbUpdate(array $update) {
+    return $this->capacitor->dbUpdate($update);
+  }
+
   function close(): void {
     $this->capacitor->close();
   }